The last words transmitted from the missing Malaysia Airlines jet to air traffic controllers were “Alright, good night”, according to an official.

Kuala Lumpur’s ambassador to Beijing, Iskandar Sarudin,
reportedly told Chinese relatives about the final message relayed
from the cockpit to authorities before flight MH370 was due to
enter Vietnamese airspace.

Mr Sarudin was speaking to the friends and relatives of some of
the 153 Chinese nationals missing, feared dead after the Boeing 777
went missing en route to Beijing more than four days ago.

Today, authorities have admitted they do not know which
direction the plane, carrying 239 passengers, was heading when it
disappeared – greatly complicating the ongoing search mission.

Amid the intensifying confusion and in the wake of at times
contradictory statements, the Malaysia’s civil aviation authorities
and military said the plane may have turned back from its last
known position between Malaysia and Vietnam, possibly as far as the
Strait of Malacca, a busy shipping lane west of Malaysia.

How it might have done this without being clearly detected
remains a mystery, raising questions over whether its electrical
systems, including transponders allowing it to be identified by
radar, were either knocked out or turned off. If it did manage to
fly on, it would challenge earlier theories that the plane may have
suffered a catastrophic incident, initially thought reasonable
because it didn't send out any distress signals.

Vietnamese officials gave conflicting accounts of whether the
search effort there was being scaled back as a result of the
confusion.

Authorities have not ruled out any possible cause, including
mechanical failure, pilot error, sabotage or terrorism. Both the
Boeing 777 and Malaysia Airlines have excellent safety records.
Until wreckage or debris is found and examined, it will be very
hard to say what happened.

The search for the missing aircraft was begun from the spot it
was last reported to be over the ocean between Malaysia and
Vietnam. But Malaysian authorities have said search operations were
ongoing in the Strait of Malacca. Scores of planes and aircraft
have been scouring waters in both locations.

The country's air force chief, Gen. Rodzali Daud, released a
statement denying remarks attributed to him in a local media report
saying that military radar had managed to track the aircraft
turning back from its original course, crossing the country and
making it to the Malacca strait.

Rodzali referred to a statement he said he made on 9March in
which he said the air force has “not ruled out the possibility of
an air turn back” and said search and rescue efforts had been
expanded to the waters around Penang Island, in the northern
section of the strait.

“There is a possibility of an air turn back. We are still
investigating and looking at the radar readings,” the country's
civilian aviation chief Azharuddin Abdul Rahman said on
Wednesday.